Evaluation of the NDMP and dump command method of archiving

The NDMP and the dump command are the most efficient methods of creating archives of the LUN drive files, you archive more data than you need.

Advantages

Because the NDMP and the dump command methods do not rely on mounting a Snapshot copy, you do not risk creating of busy Snapshot copies.
Because the NDMP and the dump command methods archive the entire raw LUN, restoring involves replacing the LUNs.
If your archive procedure does not send the data over the network, the NDMP and the dump command methods can be significantly faster than other methods.

Because you are archiving raw LUNs, the entire LUN containing the Exchange data is archived, so you archive more data than you need.
If archiving extra data is undesirable, you can use NTBackup or another Windows backup utility to back up the corresponding SnapInfo directory. Coordinate this so that the two pieces of the archive are kept together for later retrieval.
If you archive the SnapInfo directory separately, you must ensure that you get the SnapInfo directory backed up directly from the Exchange server and the Exchange data extracted from the LUN backed by Snapshot copy from different locations into the same archive.